JP6045909B2 - Polyester resin composition for circuit breakers - Google Patents

Description

  The present invention relates to a polyester resin composition for circuit breakers, and more particularly to a polyester resin composition for circuit breakers such as safety breakers and earth leakage breakers.

  Thermoplastic polyester resins such as polybutylene terephthalate are widely used in automotive materials, electrical and electronic equipment materials, housing materials, and parts manufacturing materials in other industrial fields, taking advantage of their excellent injection moldability and mechanical properties. It's being used.

Circuit breakers such as safety breakers and earth leakage circuit breakers are designed to cut off current when a current exceeding the specified level flows, or when abnormalities such as shaking or heat generation are detected. It is indispensable for ensuring the safety of electrical wiring. In recent years, in the electrical and electronic field such as breakers, it has been required to satisfy various safety tests in order to ensure a higher level of safety.
For example, as the characteristics that must be satisfied as a circuit breaker material, the flame retardance standard in the UL94 test is V-0 or higher, the red-hot ignition temperature (abbreviation: GWIT value) is 0.75 mm, and 1. All of the test pieces having thicknesses of 5 mm and 3.0 mm have a temperature of 775 ° C. or more. Furthermore, the hot-wire ignition (HWI) test is a PLC (Performance Level Category) rank 0 (= Strict characteristics are recently required, such as being desirably 120 seconds or longer).

  In order to satisfy these requirements, a flame retardant is blended. As a method for imparting flame retardancy to a polybutylene terephthalate resin, a method of blending a halogen-based organic compound as a flame retardant and an antimony compound as a flame retardant aid is common, but the above-mentioned safety test items are achieved. In order to achieve this, a large amount of flame retardant needs to be blended, and the mechanical strength balance and fluidity deteriorate.

  In addition, due to the increase in environmental awareness, it has been strongly desired to use a non-halogen flame retardant containing no halogen. For example, Patent Document 1 and Patent Document 2 disclose that a phosphinate and a nitrogen-containing compound are blended as non-halogen flame retardants, but the molded product obtained by injection molding has mechanical properties, fluidity. There was a problem that it was inferior in performance and tracking resistance. Patent Document 3 discloses that an aromatic phosphate ester and melamine cyanurate are blended as a non-halogen flame retardant, but the molded product obtained by injection molding has a gas generation amount during high-temperature heating. There was a problem that there were many and poor fluidity.

Moreover, since the resin material for circuit breakers is a material mainly used for the housing, the UL94 flame retardant standard, GWIT, and HWI must be achieved in a state where the inorganic filler is blended. Furthermore, in recent years, it has been required to be excellent in strength, hydrolysis resistance, arc resistance, etc., and the techniques proposed so far cannot solve these problems, and the solution is not possible. It was essential.
Therefore, there has been a long-awaited development of a new technology that can solve the above-described problems and satisfy the recent requirements for circuit breaker materials.

Japanese Patent Laid-Open No. 11-60924 JP 2004-263188 A Japanese Patent Laid-Open No. 03-281652

  The object (object) of the present invention is to achieve the advanced UL94 flame retardant standard, GWIT standard and HWI standard as described above, and is excellent in strength, arc resistance and hydrolysis resistance, and is used for circuit breakers. It is in providing the polyester-type resin composition for this.

The inventor has a flat cross-section glass fiber containing a specific flat cross section as a reinforcing filler, containing a specific amount of a bromine-based flame retardant, a triazine-based flame retardant, and an antimony-based flame retardant aid in a polybutylene terephthalate resin. It has been found that a polyester resin composition containing a specific amount solves the above problems, and has completed the present invention.
The present invention provides the following polyester resin composition for circuit breakers.

[1] For 100 parts by mass of polybutylene terephthalate resin (A), bromine-based flame retardant (B) 5-30 parts by mass, triazine-based flame retardant (C) 5-40 parts by mass, antimony-based flame retardant aid (D 2) 12 to 12 parts by mass and 35 to 100 parts by mass of flat cross-section glass fiber (E) having an average value of the major axis / minor axis ratio (major axis / minor axis) of 1.5 to 8 Polyester resin composition for circuit breakers.
[2] The polyester resin composition for circuit breakers according to the above [1], wherein the brominated flame retardant (B) is brominated polystyrene and / or pentabromobenzyl polyacrylate.
[3] The polyester resin composition for circuit breakers according to the above [1] or [2], wherein the triazine flame retardant (C) is melamine cyanurate.
[4] The hot wire ignition (HWI) test in accordance with ASTM D3874 of the molded product having a thickness of 1.6 mm is PLC rank 0, and the red hot rod ignition temperature (GWIT) in accordance with IEC 60695-2-13 is 775 ° C. or higher. The polyester resin composition for circuit breakers according to any one of the above [1] to [3].

  The polyester resin composition of the present invention achieves high flame retardancy, GWIT and HWI, and is excellent in strength, arc resistance, and hydrolysis resistance, so it is used for circuit breakers such as safety breakers and earth leakage breakers. It can use especially suitably for a member.

[Summary of Invention]
The polyester resin composition for circuit breakers of the present invention is 5 to 30 parts by mass of a brominated flame retardant (B) and 5 to 40 parts by mass of a triazine flame retardant (C) with respect to 100 parts by mass of the polybutylene terephthalate resin (A). Part, antimony flame retardant aid (D) 2 to 12 parts by mass and the ratio of the major axis to the minor axis (major axis / minor axis) is 1.5 to 8 flat section glass fiber (E) 35 to 100 It contains a part by mass.

Hereinafter, the contents of the present invention will be described in detail.
The description of each constituent element described below may be made based on typical embodiments and specific examples of the present invention, but the present invention is interpreted to be limited to such embodiments and specific examples. It is not a thing. In the specification of the present application, “to” is used in the sense of including the numerical values described before and after it as the lower limit value and the upper limit value.

[Polybutylene terephthalate resin (A)]
The polybutylene terephthalate resin (A) which is the main component of the polyester resin composition of the present invention is a polycondensation of a dicarboxylic acid compound containing terephthalic acid as a main component and a diol compound containing 1,4-butanediol as a main component. Polyester obtained by polycondensation or the like, and may be either a homopolyester or a copolyester.

As the dicarboxylic acid compound other than terephthalic acid constituting the polybutylene terephthalate resin (A), an aromatic dicarboxylic acid other than terephthalic acid or an ester-forming derivative thereof is preferably used.
As aromatic dicarboxylic acids, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2, 2′-dicarboxylic acid, biphenyl-3 , 3′-dicarboxylic acid, biphenyl-4,4′-dicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, diphenylmethane-4,4′-dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, diphenylisopropyl Redene-4,4′-dicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4′-dicarboxylic acid, anthracene-2,5-dicarboxylic acid, anthracene-2,6-dicarboxylic acid, p-terphenylene Examples include -4,4'-dicarboxylic acid and pyridine-2,5-dicarboxylic acid.

These aromatic dicarboxylic acids may be used as a mixture of two or more. As is well known, these can be used in polycondensation reactions as ester-forming derivatives such as dimethyl esters in addition to free acids.
In a small amount, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, dodecanedioic acid, sebacic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid 1 or more types of alicyclic dicarboxylic acids, such as these, can be mixed and used.

Examples of diol compounds other than 1,4-butanediol constituting the polybutylene terephthalate resin (A) include ethylene glycol, propylene glycol, hexylene glycol, neopentyl glycol, 2-methylpropane-1,3-diol, diethylene glycol, Aliphatic diols such as triethylene glycol, alicyclic diols such as cyclohexane-1,4-dimethanol, and mixtures thereof. If the amount is small, one or more kinds of long-chain diols having a molecular weight of 400 to 6,000, that is, polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, and the like may be copolymerized.
In addition, aromatic diols such as hydroquinone, resorcin, naphthalenediol, dihydroxydiphenyl ether, and 2,2-bis (4-hydroxyphenyl) propane can also be used.

  In addition to the above-mentioned bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane are introduced to introduce a branched structure, and fatty acids are used for molecular weight control. A small amount of a monofunctional compound can be used in combination.

  As polybutylene terephthalate resin (A), it is usually preferable that 50 mass%, preferably 70 mass% or more of the whole resin is derived from terephthalic acid and 1,4-butanediol. Of these, those in which 95 mol% or more of the acidic component is derived from terephthalic acid and 95 mass% or more of the alcohol component are derived from 1,4-butanediol are preferred.

  The intrinsic viscosity of the polybutylene terephthalate resin (A) is preferably 0.5 to 2 dl / g. From the viewpoint of moldability and mechanical properties, those having an intrinsic viscosity in the range of 0.6 to 1.5 dl / g are preferred. If the intrinsic viscosity is lower than 0.5 dl / g, the resulting resin composition tends to have a low mechanical strength. On the other hand, if it is higher than 2 dl / g, the fluidity of the resin composition may deteriorate and the moldability may deteriorate. The intrinsic viscosity of the polyester resin is measured at 30 ° C. in a 1: 1 (mass ratio) mixed solvent of 1,1,2,2-tetrachloroethane and phenol.

[Brominated flame retardant (B)]
The brominated flame retardant (B) contained in the polyester resin composition of the present invention includes brominated polycarbonate resin, brominated epoxy compound, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol. Various bromine compounds such as A, glycidyl brominated bisphenol A, brominated benzyl poly (meth) acrylates such as pentabromobenzyl polyacrylate, brominated imides (brominated phthalimide, etc.), brominated benzyl poly (meth) acrylate Brominated polystyrene, brominated epoxy compounds, and brominated aromatic polycarbonate oligomers are preferable, and brominated benzyl poly (meth) acrylate and brominated polystyrene are more preferable from the viewpoint of arc resistance.

Examples of the brominated polystyrene include brominated polystyrene containing a repeating unit represented by the following general formula.
(In the formula, t is an integer of 1 to 5, and n is the number of repeating units.)

Brominated polystyrene may be either brominated polystyrene or produced by polymerizing brominated styrene monomers, but the polymerized brominated styrene is free bromine (atom) This is preferable because the amount is small.
In the above general formula, the CH group to which brominated benzene is bonded may be substituted with a methyl group. The brominated polystyrene may be a copolymer obtained by copolymerizing another vinyl monomer. Examples of the vinyl monomer in this case include styrene, α-methylstyrene, acrylonitrile, methyl acrylate, butadiene, and vinyl acetate. Moreover, brominated polystyrene may be used as a single substance or a mixture of two or more different structures, and may contain units derived from styrene monomers having different numbers of bromines in a single molecular chain.

  Specific examples of brominated polystyrene include, for example, poly (4-bromostyrene), poly (2-bromostyrene), poly (3-bromostyrene), poly (2,4-dibromostyrene), poly (2,6 -Dibromostyrene), poly (2,5-dibromostyrene), poly (3,5-dibromostyrene), poly (2,4,6-tribromostyrene), poly (2,4,5-tribromostyrene) , Poly (2,3,5-tribromostyrene), poly (4-bromo-α-methylstyrene), poly (2,4-dibromo-α-methylstyrene), poly (2,5-dibromo-α- Methyl (styrene), poly (2,4,6-tribromo-α-methylstyrene), poly (2,4,5-tribromo-α-methylstyrene) and the like, and poly (2,4,6-tribromo). styrene ), Poly (2,4,5-tribromostyrene) and polydibromostyrene and polytribromostyrene containing an average of 2 to 3 bromine groups in the benzene ring are particularly preferably used.

The brominated polystyrene preferably has a number n (average degree of polymerization) of repeating units in the above general formula of 30 to 1,500, more preferably 150 to 1,000, particularly 300 to 800. . If the average degree of polymerization is less than 30, blooming tends to occur. On the other hand, if it exceeds 1,500, poor dispersion tends to occur and the mechanical properties tend to deteriorate. The mass average molecular weight (Mw) of brominated polystyrene is preferably 5,000 to 500,000, more preferably 10,000 to 500,000, and 10,000 to 300,000. More preferably, it is preferably 10,000 to 70,000.
In particular, in the case of the brominated product of polystyrene described above, the mass average molecular weight (Mw) is preferably 50,000 to 70,000, and in the case of brominated polystyrene by a polymerization method, the mass average molecular weight (Mw) is 10 It is preferable that it is about 8,000-80,000. In addition, a mass average molecular weight (Mw) can be calculated | required as a value of standard polystyrene conversion by a gel permeation chromatography (GPC) measurement.

Moreover, as a brominated epoxy compound, the bisphenol A brominated epoxy compound represented by tetrabromobisphenol A epoxy is mentioned, for example.
The molecular weight of the brominated epoxy compound is not particularly limited. An oligomer may be used in combination as the brominated epoxy compound. When using an oligomer as a brominated epoxy compound. For example, by using about 0 to 50% by mass of an oligomer having a molecular weight of 5000 or less, flame retardancy, releasability and fluidity can be satisfied.

Furthermore, as a brominated aromatic polycarbonate oligomer, tetrabromobisphenol A (sometimes abbreviated as “TBA”) is reacted (condensation polymerization) with phosgene or a carbonic acid diester using an appropriate molecular weight regulator. The brominated aromatic polycarbonate oligomer obtained by this is preferable. Further, it may be a copolymer type in which a part of tetrabromobisphenol A is substituted with another dihydric phenol, and the dihydric phenol described in the above aromatic polycarbonate resin is used as the other dihydric phenol. Furthermore, bisphenol A (sometimes abbreviated as “BPA”) is preferable from the viewpoint of yield during synthesis, ease of solidification, and high versatility (price).
When such a brominated aromatic polycarbonate oligomer has a degree of polymerization of 1, it tends to bleed out from the molded product at the time of molding, and on the other hand, when the degree of polymerization increases, it becomes difficult to obtain satisfactory fluidity. The preferred degree of polymerization is 2-15.

Brominated aromatic polycarbonate oligomers that satisfy the above conditions are commercially available and can be easily obtained. For example, an oligomer (average degree of polymerization of 5) obtained by reacting TBA and phosgene using 2,4,6-tribromophenol (sometimes abbreviated as “TBPH”) as a molecular weight regulator is Mitsubishi Engineering. It is commercially available from Plastics Co., Ltd. under the trade name “Iupilon FR-53”.
The brominated aromatic polycarbonate oligomer may be used alone or in combination of two or more. Moreover, as long as the characteristic of this invention is not impaired, other brominated flame retardants other than a bromine containing aromatic polycarbonate oligomer can also be used together.

  Brominated benzyl poly (meth) acrylate is a polymer obtained by polymerizing benzyl (meth) acrylate containing a bromine atom alone, copolymerizing two or more kinds, or copolymerizing with other vinyl monomers. The bromine atom is preferably added to a benzene ring, and the number of addition is preferably 1 to 5, more preferably 4 to 5 per benzene ring.

Examples of the benzyl acrylate containing a bromine atom include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, and mixtures thereof. Examples of the benzyl methacrylate containing a bromine atom include methacrylates corresponding to the acrylates described above.
Among these, pentabromobenzyl acrylate is particularly preferable.

Specific examples of other vinyl monomers used for copolymerization with benzyl (meth) acrylates containing bromine atoms include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and benzyl acrylate. Acrylic acid esters, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacrylic acid esters such as benzyl methacrylate, unsaturated carboxylic acids such as styrene, acrylonitrile, fumaric acid, maleic acid, or anhydrides thereof, vinyl acetate And vinyl chloride.
These are usually preferably used in an equimolar amount or less, particularly 0.5 times the molar amount or less with respect to benzyl (meth) acrylate containing a bromine atom.

  In addition, xylene diacrylate, xylene dimethacrylate, tetrabromoxylene diacrylate, tetrabromoxylene dimethacrylate, butadiene, isoprene, divinylbenzene, etc. can be used as vinyl monomers, and these usually contain bromine atoms. The benzyl acrylate or benzyl methacrylate can be used at a molar amount of 0.5 times or less.

  As the brominated benzyl poly (meth) acrylate, pentabromobenzyl polyacrylate has a high bromine content and is particularly preferable in terms of arc resistance.

The brominated flame retardant (B) preferably has a bromine concentration of 52 to 75% by mass, more preferably 56 to 73% by mass, and even more preferably 57 to 72% by mass. By setting the bromine concentration in such a range, it is easy to keep good flame retardancy.
Further, the content of free bromine in the brominated flame retardant (B) is preferably 0.5% by mass or less, more preferably 0.45% by mass or less, and 0.4% by mass or less. More preferably it is. When the content of free bromine exceeds 0.5% by mass, the amount of free bromine in the resin composition finally obtained increases, and is desorbed when the resin composition is at a high temperature during processing or molding. In some cases, the heat discoloration resistance, color tone, and light discoloration stability of the resin composition may be deteriorated, or metal corrosion of a mold or the like may be caused during molding. Also, removing the free bromine content up to 0% by mass requires purification so as not to be economical, so the lower limit of the content is usually 0.001% by mass and 0.005% by mass. %, And more preferably 0.01% by mass.

  Further, the chlorine content in the brominated flame retardant (B) is preferably 0.2% by mass or less, more preferably 0.15% by mass or less, and 0.08% by mass or less. More preferably, it is especially preferable that it is 0.03 mass% or less. When the content of chlorine in the brominated flame retardant (B) exceeds 0.2% by mass, the chlorine content in the resin composition finally obtained tends to be too large, and the tracking resistance and toughness tend to deteriorate. It is in.

  Furthermore, the content of sulfur in the brominated flame retardant (B) is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and 0.02% by mass or less. More preferably. If the sulfur content in the brominated flame retardant (B) exceeds 0.1% by mass, the sulfur content in the finally obtained resin composition will increase too much, resulting in tracking resistance and mold corrosion resistance. Tend to get worse.

  The content of free bromine, chlorine and sulfur in the brominated flame retardant (B) can be measured by a combustion ion chromatography method. Specifically, it was generated by heating a brominated flame retardant (B) under the conditions of 270 ° C. and 10 minutes in an argon atmosphere using an automatic sample combustion apparatus of “AQF-100 type” manufactured by Mitsubishi Chemical Analytech. The amount of bromine, chlorine and sulfur can be determined by quantifying using “ICS-90” manufactured by Nippon Dionex.

  Content of a brominated flame retardant (B) is 5-30 mass parts with respect to 100 mass parts of polybutylene terephthalate resins (A). When the content is less than 5 parts by mass, a sufficient flame retarding effect cannot be obtained, and when it exceeds 30 parts by mass, the mechanical strength is lowered. The preferred content of the brominated flame retardant (B) is 10 parts by mass or more, more preferably 15 parts by mass or more, preferably 26 parts by mass or less, relative to 100 parts by mass of the polybutylene terephthalate resin (A). More preferably, it is 23 parts by mass or less.

[Triazine flame retardant (C)]
Examples of the triazine flame retardant (C) used in the present invention include compounds represented by the following general formula (1) or (2), melamines, and melamine cyanurate.

(Wherein R ^{1 to} R ⁶ each represent a hydrogen atom or an alkyl group).

  Specific examples of the compound represented by the general formula (1) include cyanuric acid, trimethylcyanurate, triethylcyanurate, tri (n-propyl) cyanurate, methylcyanurate, diethylcyanurate and the like. Specific examples of the compound represented by the general formula (2) include isocyanuric acid, trimethyl isocyanurate, triethyl isocyanurate, tri (n-propyl) isocyanurate, diethyl isocyanurate, methyl isocyanurate and the like.

Examples of melamines include melamine, melamine derivatives, compounds having a structure similar to melamine, and melamine condensates. Specific examples of melamines include melamine, ammelide, ammelin, formoguanamine, guanylmelamine, cyanomelamine, arylguanamine, melam, melem, melon and the like.
Examples of melamine cyanurate include equimolar reaction products of cyanuric acid and melamine. Moreover, some of the amino groups or hydroxyl groups in melamine cyanurate may be substituted with other substituents. Melamine cyanurate can be obtained, for example, by mixing an aqueous solution of cyanuric acid and an aqueous solution of melamine, reacting at 90 to 100 ° C. with stirring, and filtering the produced precipitate, and is a white solid. It is preferable to use after pulverizing into a powder form. Of course, a commercially available product can be used as it is or after being pulverized.

  Preferred examples of the triazine flame retardant (C) used in the present invention include cyanuric acid, isocyanuric acid, melamine, melamine cyanurate, and melem cyanuric acid, and the decomposition product emerges on the surface of the molded product. Since there is no inconvenience such as blooming, an equimolar reaction product of cyanuric acid represented by melamine cyanurate and melamine is more preferable. However, since melamine cyanurate starts to decompose at 260 ° C. or higher, it is necessary to avoid the molding temperature at 260 ° C. or higher in order to suppress the occurrence of molding defects and ensure flame retardancy.

  The content of the triazine flame retardant (C) is 5 to 40 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin (A). If the content of the triazine flame retardant is less than 5 parts by mass, the flame retardancy effect, HWI characteristics, and insulation characteristics after the arc resistance test are not expected. When the amount is more than 40 parts by mass, mold contamination is a problem because it is easily decomposed during molding. The content of the triazine-based flame retardant (C) is preferably 7 to 30 parts by mass, more preferably 9 to 25 parts by mass, from the viewpoint of the balance between flame retardancy and GWIT characteristics, HWI characteristics, and mechanical characteristics. is there.

[Antimony flame retardant aid (D)]
Examples of the antimony flame retardant aid (D) contained in the polyester resin composition of the present invention include antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), and sodium antimonate. However, antimony trioxide and sodium antimonate are preferable.
The content of the antimony flame retardant auxiliary (D) is 2 to 12 parts by mass, more preferably 4 parts by mass or more, and preferably 10 masses with respect to 100 parts by mass of the polybutylene terephthalate resin (A). Or less. When the content of the antimony flame retardant aid is less than 2 parts by mass, the flame retardancy is lowered, and when it exceeds 12 parts by mass, mechanical properties such as impact resistance are lowered.

  The mass concentration of the bromine atom derived from the brominated flame retardant (B) and the antimony atom derived from the antimony based flame retardant auxiliary (D) in the polyester resin composition is 3 to 25 mass% in total. Is preferable, and it is more preferable that it is 4-22 mass%. If it is less than 3% by mass, the flame retardancy tends to be reduced, and if it exceeds 25% by mass, the mechanical strength, GWIT characteristics, and HWI standard characteristics may be reduced. The mass ratio (Br / Sb) of bromine atoms and antimony atoms is preferably 0.3 to 5, and more preferably 0.3 to 4.

[Flat cross section glass fiber (E)]
The glass fiber contained in the polyester resin composition of the present invention is a flat cross-section glass fiber (E) having an average value of the major axis to minor axis ratio (major axis / minor axis) of 1.5 to 8. By using such a glass fiber, the mechanical properties such as flame retardancy, HWI characteristics, arc resistance, hydrolysis resistance and bending strength of the polybutylene terephthalate resin composition of the present invention can be effectively enhanced. it can.

  The average value of the major axis of the fiber cross section of the flat cross-section glass fiber (E) is preferably 10 to 50 μm, more preferably 15 to 40 μm, still more preferably 20 to 35 μm, and particularly preferably 25 to 30 μm. The average value of the minor axis is preferably 0.5 to 30 μm, more preferably 2 to 20 μm, and further preferably 4 to 10 μm.

  In addition, the average value of the ratio of the major axis to the minor axis (major axis / minor axis) of the flat cross-section glass fiber (E) is 1.5 to 8, preferably 2 to 7, more preferably 2.5 to 6. More preferably, it is 3-5. By using a flat cross-section glass fiber having an average value of the major axis and minor axis ratio (major axis / minor axis) in such a range, the flowability, low warpage, and impact resistance of the polyester resin composition of the present invention can be improved. Can be increased.

  The flat cross-section glass fiber (E) used in the present invention is not particularly limited as long as the cross-sectional shape is non-circular, and is an oval shape having a portion that is substantially parallel to a symmetrical position with respect to the center of the cross-section. Ellipse, saddle, semicircle, arc, rectangle, trefoil, and similar non-circular shapes are included, but long in terms of mechanical strength, low warpage, and anisotropy. A circular shape, an elliptical shape, and a bowl shape are preferable, and an oval shape is particularly preferable.

The cross-sectional area of the flat cross-section glass fiber (E) is preferably 2 × 10 ⁻⁵ to 8 × 10 ⁻³ mm ² , more preferably 8 × 10 ⁻⁵ to 8 × 10 ⁻³ mm ² , and even more preferably 8 ×. 10 ⁻⁵ to 8 × 10 ⁻⁴ mm ² . It is preferable that the cross-sectional area is 2 × 10 ⁻⁵ mm ² or more because handling at the time of producing resin composition pellets used for producing and molding glass fibers becomes easy. Furthermore, when the glass fiber within the above cross-sectional area range is used, the contact area with the polybutylene terephthalate resin is increased, and a sufficient reinforcing effect can be obtained.
The ratio of the major axis to the minor axis and the cross-sectional area of the cross section of the glass fiber are obtained by observing the cross section of the glass fiber used for the production of the resin composition with a microscope at an appropriate magnification, and the obtained image is image analysis software, for example, Planetron It can be obtained by measuring the actual size of 2000 glass fibers using image analysis software such as “Image-Pro Plus” manufactured by the company, and averaging the obtained values.

Moreover, the ratio (aspect ratio) of the average fiber length and the average fiber diameter of the flat cross-section glass fiber (E) is usually 2 to 120, preferably 2.5 to 70, and more preferably 3 to 50. When the ratio of the average fiber length to the average fiber diameter (aspect ratio) of the flat cross-section glass fiber (E) is less than 2, the mechanical strength tends to decrease. In addition to increasing the directivity, the appearance of the molded product tends to be remarkably deteriorated.
The average fiber diameter of the flat cross-section glass fiber (E) refers to the number average fiber diameter when the flat cross-sectional shape is converted into a true circle having the same area. The average fiber length refers to the number average fiber length in the polyester resin composition of the present invention. The number-average fiber length is calculated by an image analyzer from an image obtained by observing a filler residue collected by a process such as high-temperature ashing of a molded product, dissolution with a solvent, and decomposition with a chemical with an optical microscope. Value. Further, when calculating such a value, the fiber diameter is used as a guide and the length is less than that.

Various glass compositions represented by A glass, C glass, E glass, etc. are applied to the glass composition of the flat cross-section glass fiber (E), and it is not particularly limited. Such glass fiber (E) may contain components such as TiO ₂ , SO ₃ , P ₂ O ₅ , CaO, MgO, B ₂ O ₃ as necessary. Among these, E glass (non-alkali glass) is preferable because the mechanical strength and thermal stability of the polyester resin composition of the present invention are increased.

  The flat cross-section glass fiber (E) used in the present invention is a silane coupling agent such as aminosilane or epoxysilane, titanate coupling agent, aluminate cup for the purpose of improving the adhesion to the polybutylene terephthalate resin (A). Surface treatment can be performed with a ring agent or the like.

Further, the flat cross-section glass fiber (E) used in the present invention is usually preferably used as a chopped strand (chopped glass fiber) obtained by cutting a number of these fibers into a predetermined length. Sometimes, the flat cross-section glass fiber (E) used in the present invention preferably contains a sizing agent.
The sizing agent is not particularly limited, and examples thereof include urethane-based, epoxy-based, acrylic-based, polyester-based, styrene-based and olefin-based sizing agents. Among them, as the sizing agent for the flat cross-section glass fiber (E) used in the present invention, urethane-based and epoxy-based sizing agents are more preferable, and epoxy-based sizing agents are more preferable.
In addition, the adhesion amount of a sizing agent is 0.1-3 mass% normally in 100 mass% of flat cross-section glass fibers (E), Preferably it is 0.2-1 mass%.

[Boric acid metal salt]
The polyester resin composition of the present invention preferably contains a metal borate.
Examples of the boric acid metal salt include alkali metal salts of boric acid (for example, sodium tetraborate, potassium metaborate) or alkaline earth metal salts (for example, calcium borate, magnesium orthoborate, barium orthoborate, zinc borate). It is done. Among these, zinc borate is preferable. Zinc borate is generally represented by 2ZnO · 3B ₂ O ₃ · xH ₂ O (x = 3.3 to 3.7). The hydrated zinc borate is preferably one having the formula 2ZnO · 3B ₂ O ₃ · 3.5H ₂ O and stable up to a temperature of 260 ° C. or higher.

Colemanite is an example of calcium borate. Colemanite is an inorganic compound mainly composed of calcium borate and is usually a hydrate represented by the chemical formula 2CaO · 3B ₂ O ₃ · 5H ₂ O. The colemanite used in the present invention may be any one of colemanite, colemanite or calcium borate or soluite, or a synthetic material. Among them, the colemanite produced as a mineral is thermally stable. Since it is excellent in property, it is preferable.

  The amount of the boric acid metal salt may be appropriately selected and determined. However, if the amount is too large, the mechanical properties tend to decrease. On the other hand, if the amount is too small, the effect of addition is insufficient. ) It is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 4 parts by mass, more preferably 1 to 3 parts by mass, and particularly preferably 1 to 2 parts by mass with respect to 100 parts by mass.

[Carbon black]
The polyester-based resin composition of the present invention preferably further contains carbon black. The inclusion of carbon black improves weather resistance as a circuit breaker material.
The carbon black used in the present invention is not limited in type, raw material type, and manufacturing method, and any of furnace black, channel black, acetylene black, ketjen black, and the like can be used. The number average particle size is not particularly limited, but is preferably 5 to 60 nm. As described above, by using carbon black having a number average particle diameter in a predetermined range, a composition in which blisters are hardly generated at a high temperature can be obtained.

Nitrogen adsorption specific surface area of the carbon black ^{(unit: m} 2 / g) is preferably usually less than 1000 m ² / g, is preferably Among them 50 to 400 m ² / g. By making the nitrogen adsorption specific surface area less than 1000 m ² / g, the flowability of the polyester resin composition of the present invention and the appearance of the molded product tend to be improved, which is preferable. The nitrogen adsorption specific surface area can be measured according to JIS K6217.

The DBP (dibutyl phthalate) absorption amount of carbon black ^is preferably less than 300 cm 3/100 g, is preferably Among them 30~200cm ³ / 100g. The DBP absorption amount by less than 300 cm ^3/100 g, preferably tends to increase the appearance of fluidity and a molded article of the polyester resin composition of the present invention.
Incidentally, DBP absorption ^(unit: cm 3 / 100g) can be measured according to JIS K6217. The carbon black used in the present invention is not particularly limited with respect to its pH, but it is usually 2 to 10, preferably 3 to 9, and more preferably 4 to 8.

  Carbon black can be used alone or in combination of two or more. Furthermore, carbon black can be granulated using a binder, and can also be used in a masterbatch that is melt-kneaded at a high concentration in another resin. By using the melt-kneaded master batch, the handling property during extrusion and the dispersibility improvement in the resin composition can be achieved. Examples of the resin include polybutylene terephthalate resin, polystyrene resin, polycarbonate resin, acrylic resin, and among them, polystyrene resin such as acrylonitrile-styrene resin is preferable.

  The content of carbon black is preferably 0.001 to 5 parts by mass or more, more preferably 0.002 parts by mass or more, and still more preferably 0.001 parts by mass or more with respect to 100 parts by mass of the polybutylene terephthalate resin (A). 003 parts by mass or more, more preferably 4.5 parts by mass or less, further preferably 4 parts by mass or less, and particularly preferably 3.5 parts by mass or less.

[Stabilizer]
It is preferable that the polyester-based resin composition of the present invention further contains a stabilizer because it has effects of improving thermal stability and preventing deterioration of mechanical strength and hue. As the stabilizer, a phosphorus stabilizer and a phenol stabilizer are preferable.

  Examples of the phosphorus-based stabilizer include phosphorous acid, phosphoric acid, phosphite ester, and phosphate ester. Among them, organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds are preferable.

The organic phosphate compound is preferably the following general formula:
(R ¹ O) _3-n P (═O) OH _n
(In the formula, R ¹ is an alkyl group or an aryl group, and may be the same or different. N represents an integer of 0 to 2.)
It is a compound represented by these. More preferably, R ¹ is a long-chain alkyl acid phosphate compound having 8 to 30 carbon atoms. Specific examples of the alkyl group having 8 to 30 carbon atoms include octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, A hexadecyl group, an octadecyl group, an eicosyl group, a triacontyl group, etc. are mentioned.

Examples of the long-chain alkyl acid phosphate include octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, octadecyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonyl phenyl acid phosphate Acid phosphate, phenoxyethyl acid phosphate, alkoxy polyethylene glycol acid phosphate, bisphenol A acid phosphate, dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, geo Chill acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, diphenyl acid phosphate, and a bis-nonylphenyl acid phosphate, or the like.
Among these, octadecyl acid phosphate is preferable, and this is marketed under the trade name “ADEKA STAB AX-71” of ADEKA.

As the organic phosphite compound, preferably, the following general formula:
^{R 2 O-P (OR 3} ) (OR 4)
Wherein R ² , R ³ and R ⁴ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and at least one of R ² , R ³ and R ⁴ One is an aryl group having 6 to 30 carbon atoms.)
The compound represented by these is mentioned.

  Examples of the organic phosphite compound include triphenyl phosphite, tris (nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris (2-ethylhexyl) phosphite, and tris (tridecyl). ) Phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono (tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite Hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4′-butylidene-bis (3-methyl-6-t rt-butylphenyldi (tridecyl) phosphite), tetra (tridecyl) 4,4′-isopropylidenediphenyldiphosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, di Lauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris (4-tert-butylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite Phytopolymer, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite Phosphite, 2,2'-methylenebis (4,6-di -tert- butylphenyl) octyl phosphite, bis (2,4-dicumylphenyl) pentaerythritol diphosphite and the like.

The organic phosphonite compound is preferably the following general formula:
R ⁵ -P (OR ⁶ ) (OR ⁷ )
(Wherein R ⁵ , R ⁶ and R ⁷ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms, and at least one of R ⁵ , R ⁶ and R ⁷ ) One is an aryl group having 6 to 30 carbon atoms.)
The compound represented by these is mentioned.

  Examples of the organic phosphonite compound include tetrakis (2,4-di-iso-propylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-di-n-butylphenyl) -4,4′-biphenyl. Range phosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylene diphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3'-biphenylene diphospho Knight, tetrakis (2,4-di-tert-butylphenyl) -3,3'-biphenylenediphosphonite, tetrakis (2,6-di-iso-propylphenyl) -4,4'-biphenylenediphosphonite, Tetrakis (2,6-di-n-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2, -Di-tert-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,3'-biphenylenediphosphonite, and tetrakis (2,6- And di-tert-butylphenyl) -3,3′-biphenylenediphosphonite.

One type of phosphorous stabilizer may be contained, or two or more types may be contained in any combination and ratio.
As described above, octadecyl acid phosphate that exhibits excellent compatibility and dramatically improves elongation and thin-wall toughness by combining with the polybutylene terephthalate resin (A) as described above is particularly preferable.

  Examples of the phenol-based stabilizer include pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4) -Hydroxyphenyl) propionate, thiodiethylenebis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), pentaerythritol tetrakis (3- (3,5-di-neopentyl-4-hydroxyphenyl) ) Propionate) and the like. Among these, pentaerythritol tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate is preferred.

  Content of a stabilizer is 0.001-5 mass parts with respect to 100 mass parts of polybutylene terephthalate resins (A). When the content of the stabilizer is less than 0.001 part by mass, it is difficult to expect an improvement in the thermal stability and compatibility of the resin composition, and a decrease in molecular weight and a deterioration in hue during molding are likely to occur. When it exceeds, it will become excess amount and there exists a tendency for generation | occurrence | production of silver and a hue deterioration to occur further easily. The content of the stabilizer is more preferably 0.001 to 4.5 parts by mass, still more preferably 0.005 to 4 parts by mass, and particularly preferably 0.01 to 1 part by mass.

[Epoxy compound]
It is preferable that the polyester-based resin composition of the present invention further contains a hydrolysis resistance inhibitor in that it has an effect of improving hydrolysis resistance and moist heat resistance and preventing a decrease in mechanical strength. As the hydrolysis resistance inhibitor, an epoxy compound is preferable.

  Examples of the epoxy compound include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, resorcinol type epoxy compounds, novolac type epoxy compounds, alicyclic epoxy compounds, glycidyl ethers, glycidyl esters, epoxidized butadiene polymers, and the like. Can be mentioned.

Examples of the bisphenol A type epoxy compound include bisphenol A-diglycidyl ether and hydrogenated bisphenol A-diglycidyl ether. Examples of the bisphenol F type epoxy compound include bisphenol F-diglycidyl ether and hydrogenated bisphenol F-diglycidyl ether. Examples of the resorcin type epoxy compound include resorcin diglycidyl ether.
Moreover, as a novolak-type epoxy compound, a phenol novolak-type epoxy resin, a cresol novolak-type epoxy resin, etc. can be illustrated.

  Examples of alicyclic epoxy compounds include vinylcyclohexene dioxide, dicyclopentadiene oxide, 3,4-epoxycyclohexyl-3,4-cyclohexylcarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene di Examples thereof include epoxide and 3,4-epoxycyclohexyl glycidyl ether.

  Specific examples of glycidyl ethers include monoglycidyl ethers such as methyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, decyl glycidyl ether, stearyl glycidyl ether, phenyl glycidyl ether, butylphenyl glycidyl ether, and allyl glycidyl ether; Examples include diglycidyl ethers such as pentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, propylene glycol diglycidyl ether, and bisphenol A diglycidyl ether. Examples of the glycidyl esters include monoglycidyl esters such as benzoic acid glycidyl ester and sorbic acid glycidyl ester; diglycidyl esters such as adipic acid diglycidyl ester, terephthalic acid diglycidyl ester, and orthophthalic acid diglycidyl ester. .

  Examples of the epoxidized butadiene polymer include epoxidized polybutadiene, epoxidized styrene-butadiene copolymer, and epoxidized hydrogenated styrene-butadiene copolymer.

  The epoxy compound may be a copolymer having a glycidyl group-containing compound as one component. For example, a copolymer of glycidyl ester of α, β-unsaturated acid and one or two or more monomers selected from the group consisting of α-olefin, acrylic acid, acrylic ester, methacrylic acid, methacrylic ester It is done.

  As such an epoxy compound, an epoxy compound having an epoxy equivalent of 100 to 500 g / eq and a mass average molecular weight of 2000 or less is preferable. When the epoxy equivalent is less than 100 g / eq, the viscosity of the resin composition is high because the amount of the epoxy group is too large. Conversely, when the epoxy equivalent exceeds 500 g / eq, the amount of the epoxy group decreases. The effect of improving the heat-and-moisture resistance characteristics of the resin composition is not sufficiently exhibited. When the mass average molecular weight exceeds 2000, the compatibility with the polybutylene terephthalate resin is lowered, and the mechanical strength of the molded product tends to be lowered. The epoxy compound is preferably a bisphenol A type epoxy compound or a novolac type epoxy compound obtained from a reaction of bisphenol A or novolak with epichlorohydrin.

  The content of the hydrolysis inhibitor is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and further 0.7 parts by mass or more with respect to 100 parts by mass of the polybutylene terephthalate resin (A). preferable. Further, if the content of the hydrolysis-resistant inhibitor is more than 5 parts by mass, crosslinking may proceed and the fluidity at the time of molding may be deteriorated. Therefore, it is preferably 3 parts by mass or less, more preferably 2 parts by mass or less. Part by mass or less is particularly preferable.

[Anti-drip agent]
It is also preferred that the polyester resin composition of the present invention contains an anti-dripping agent. As the anti-drip agent, polytetrafluoroethylene (PTFE) is preferable, has a fibril-forming ability, easily disperses in the resin composition, and shows a tendency to form a fibrous material by bonding the resins together. is there. Specific examples of polytetrafluoroethylene include, for example, trade names “Teflon (registered trademark) 6J” or “Teflon (registered trademark) 30J” commercially available from Mitsui DuPont Fluorochemical Co., Ltd., Daikin Industries, Ltd. Examples include the commercially available product name “Polyflon” or the product name “Fullon” marketed by Asahi Glass Co., Ltd.
The content ratio of polytetrafluoroethylene is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the polybutylene terephthalate resin (A). If the polytetrafluoroethylene having fibril forming ability is less than 0.1 parts by mass, the flame retardancy tends to be insufficient, and if it exceeds 20 parts by mass, the appearance tends to deteriorate. The content ratio of polytetrafluoroethylene is more preferably 0.2 to 10 parts by mass, and still more preferably 0.3 to 1 part by mass with respect to 100 parts by mass of the polybutylene terephthalate resin (A).

[Release agent]
The polyester resin composition of the present invention preferably further contains a release agent. As the mold release agent, known mold release agents usually used for polyester resins can be used. Among them, one or more mold release agents selected from polyolefin compounds, fatty acid ester compounds, and silicone compounds are used. preferable.

  Examples of the polyolefin compound include compounds selected from paraffin wax and polyethylene wax. Among them, those having a mass average molecular weight of 700 to 10,000, more preferably 900 to 8,000 are preferable.

Polyolefin compounds include carboxyl groups (carboxylic acid (anhydride) groups, that is, carboxylic acid groups and / or carboxylic anhydride groups; the same shall apply hereinafter), haloformyl groups, ester groups, carboxylate metal bases, hydroxyl groups. It is preferable in terms of fogging property and releasability to provide a functional group having an affinity for polybutylene terephthalate, such as an alkoxyl group, an epoxy group, an amino group, or an amide group. This concentration is preferably more than 5 mgKOH / g and less than 50 mgKOH / g, more preferably 10 to 40 mgKOH / g, more preferably 15 to 30 mgKOH / g, and particularly preferably 20 to 28 mgKOH / g as the acid value of the polyolefin compound. preferable. The acid value can be measured according to a potentiometric titration method (ASTM D1386) using a 0.5 mol KOH ethanol solution.
In addition, an oxidized polyethylene wax is preferable as the polyolefin-based compound since it has a small amount of volatile matter and at the same time has a remarkable effect of improving the releasability.

  Examples of the fatty acid ester compounds include fatty acid esters such as glycerin fatty acid esters and sorbitan fatty acid esters, and partially saponified products thereof. Among them, the fatty acid ester compounds are composed of fatty acids having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms. Preferred are mono- or di-fatty acid esters. Specifically, glycerol monostearate, glycerol monobehenate, glycerol dibehenate, glycerol-12-hydroxy monostearate, sorbitan monobehenate, etc. are mentioned.

  Moreover, as a silicone type compound, the compound modified | denatured from points, such as compatibility with a polyester resin, is preferable. Examples of the modified silicone oil include silicone oil in which an organic group is introduced into the side chain of polysiloxane, silicone oil in which an organic group is introduced into both ends and / or one end of polysiloxane, and the like. Examples of the organic group to be introduced include an epoxy group, an amino group, a carboxyl group, a carbinol group, a methacryl group, a mercapto group, and a phenol group, and preferably an epoxy group. As the modified silicone oil, a silicone oil in which an epoxy group is introduced into the side chain of polysiloxane is particularly preferable.

  It is preferable that content of a mold release agent is 0.05-2 mass parts with respect to 100 mass parts of polybutylene terephthalate resin (A). If the amount is less than 0.05 parts by mass, the surface property tends to decrease due to defective mold release at the time of melt molding. On the other hand, if it exceeds 2 parts by mass, the kneading workability of the resin composition decreases, and molding is also performed. The surface of the product may be cloudy. The content of the release agent is preferably 0.07 to 1.5 parts by mass, more preferably 0.1 to 1.0 parts by mass.

[Other ingredients]
The polyester resin composition of the present invention may further contain various additives as long as the effects of the present invention are not impaired. Examples of such additives include reinforcing fillers other than the flat cross-section glass fiber (E), UV absorbers, dyes and pigments, fluorescent whitening agents, antistatic agents, antifogging agents, lubricants, antiblocking agents, and fluidity. Examples thereof include an improver, a plasticizer, a dispersant, and an antibacterial agent.

  Moreover, the polyester resin composition in the present invention can contain a thermoplastic resin other than the polybutylene terephthalate resin within a range that does not impair the effects of the present invention. Specific examples of other thermoplastic resins include polycarbonate resins, polyethylene terephthalate resins, polyacetal resins, polyamide resins, polyphenylene oxide resins, polystyrene resins, polyphenylene sulfide resins, polysulfone resins, polyether sulfone resins, and polyethers. Examples thereof include imide resins, polyether ketone resins, and polyolefin resins.

[Method for Producing Resin Composition]
As a manufacturing method of the polyester-type resin composition of this invention, it can carry out in accordance with the conventional method of polybutylene terephthalate resin composition preparation. Usually, the components and various additives added as desired are mixed together and then melt-kneaded in a single-screw or twin-screw extruder. Moreover, it is also possible to prepare the resin composition of the present invention by mixing each component in advance or by mixing only a part of the components in advance and supplying them to an extruder using a feeder and melt-kneading them. Furthermore, a masterbatch is prepared by melt-kneading a polybutylene terephthalate resin or a part of another resin with a part of other ingredients, and then the remaining polyester resin or other ingredients are added thereto. And may be melt-kneaded.
In addition, it is also preferable to supply a flat cross-section glass fiber (E) from the side feeder in the middle of the cylinder of an extruder.

  The heating temperature at the time of melt kneading can be appropriately selected from the range of usually 220 to 300 ° C. If the temperature is too high, decomposition gas is likely to be generated, which may cause opacity. Therefore, it is desirable to select a screw configuration in consideration of shear heat generation. In order to suppress decomposition during kneading or molding in the subsequent process, it is desirable to use an antioxidant or a heat stabilizer.

[Molded products for circuit breakers]
The polyester resin composition of the present invention is used as a molded product for a circuit breaker.
Circuit breakers include circuit breakers such as breakers, electromagnetic switches, ampere breakers, earth leakage breakers, wiring breakers, motor protection breakers (motor breakers), slim breakers (one-touch breakers, one-touch breakers). Is mentioned. The molded product for the circuit breaker is a molded product or member such as a cover, a housing, or a casing of the circuit breaker.
The manufacturing method of a molded article is not particularly limited, and a molding method generally adopted for a polyester resin composition can be arbitrarily adopted. For example, injection molding method, ultra-high speed injection molding method, injection compression molding method, two-color molding method, hollow molding method such as gas assist, molding method using heat insulating mold, rapid heating mold were used. Molding method, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, laminate molding method, press molding method, Examples thereof include a blow molding method. Among these, it is preferable to adopt an injection molding method.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the following examples.
In the following description, “parts” means “parts by mass” based on mass standards unless otherwise specified.

  In the following Examples and Comparative Examples, the components used are as shown in Table 1 below.

(Examples 1 to 4 and Comparative Examples 1 to 6 )
Each component described in Table 2 and Table 3 below is blended so as to have a blending ratio (parts by mass) described in Tables 2-3, and using a twin screw extruder (screw diameter 35 mm), a barrel set temperature 250 Extruded resin composition pellets were produced at 200 ° C. and 200 rpm. The characteristics of the obtained pellets were evaluated for test pieces that were injection molded at a cylinder temperature of 250 ° C. using an injection molding machine (Nex80-9E, manufactured by Nissei Plastic Industry Co., Ltd.). In molding, the resin composition was dried at 120 ° C. for 6 to 8 hours until immediately before the molding.

<Evaluation method>
Each evaluation method is as follows.
(1) Bending strength Using a test piece for UL94 test (125 mm × 12.5 mm × 1.6 mmt), a three-point bending test was performed at a bending test speed of 2 mm / min, and the bending strength was measured.
(2) Flexural strength after hydrolysis A test piece for UL94 test (125 mm × 12.5 mm × 1.6 mmt) was left in a pressure cooker tester at a temperature of 121 ° C., a humidity of 100% and a pressure of 2 atm for 50 hours. The obtained test piece was subjected to a three-point bending test by the method described in (1) above, and the bending strength was measured.

(3) Flame retardancy Using flame test pieces for UL94 test (125 mm × 12.5 mm × 1.6 mmt), flame retardancy was evaluated based on the UL94 standard.

(4) Arc resistance Using a test piece of 100 mm x 100 mm x 3 mmt, an arc resistance test was performed in accordance with ASTM D495 standard. A high voltage spark discharge (12.5 kV, 10 mA) was repeated between the electrodes, and the time until the carbonized conductive path was formed was measured.
Moreover, about the carbonized conductive path part after the said arc resistance test, the resistance value at the time of 125V application was measured using the mega tester.

(5) Arc resistance after hydrolysis test A test piece of 100 mm × 100 mm × 3 mmt was left in a pressure cooker tester having a temperature of 121 ° C., a humidity of 100% and a pressure of 2 atm for 50 hours. About the obtained test piece, the arc resistance test and the measurement of the resistance value of the carbonized conductive path portion were performed by the method described in (4) above.

(6) Hot wire ignition (HWI) test A test piece of 125 mm x 12.5 mm x 1.6 mmt is compliant with ASTM D3874 standard, and a specified nichrome wire is wound five times at intervals of 6.35 m. Electric power was applied and the time until the specimen ignited was measured.

(7) Glow wire (GWIT) test Using a 60 mm x 60 mm x 1.6 mmt flat plate test piece, the test was performed according to the test method defined in the IEC 60695-2-13 standard. Specifically, a red hot rod having a predetermined shape (a nickel / chromium (80/20) wire having an outer diameter of 4 mm in a loop shape) is brought into contact with a test piece for 30 seconds, and a temperature 25 ° C. higher than the maximum temperature at the tip that does not ignite. Is defined by the red hot rod ignition temperature and the test method concerned. This temperature was measured.
The above evaluation results are shown in Table 2 and Table 3 below.

  From Tables 2-3, the polyester-based resin composition of the present invention has excellent performance for UL94 flame retardant test, GWIT test, and HWI test, and further, mechanical strength, arc resistance, and hydrolysis resistance. It can be seen that it is excellent.

  The polyester resin composition of the present invention achieves high flame retardancy, GWIT standard, and HWI standard, and is also excellent in strength, arc resistance, and hydrolysis resistance, so it is suitable as a molded product for circuit breakers. It can be applied and the industrial utility is very high.

Claims (3)

Polybutylene terephthalate resin (A) 100 parts by mass of brominated polystyrene and / or brominated flame retardants is pentabromobenzyl polyacrylate (B) 5 to 30 parts by weight of a triazine-based flame retardant (C) 9 ~ 25 mass Part, antimony flame retardant aid (D) 2 to 12 parts by mass and the ratio of the major axis to the minor axis (major axis / minor axis) is 1.5 to 8 flat section glass fiber (E) 35 to 100 A polyester-based resin composition for use in any one of a cover, a housing, and a housing of a circuit breaker characterized by containing a mass part. Triazine-based flame retardant (C) is Po Riesuteru resin composition according to claim 1 melamine cyanurate. The hot wire ignition (HWI) test according to ASTM D3874 of a molded product having a thickness of 1.6 mm is PLC rank 0, and the red hot rod ignition temperature (GWIT) according to IEC 60695-2-13 is 775 ° C. or higher. Po Riesuteru resin composition according to claim 1 or 2.